Pure practical reason is the opposite to impure (or sensibly-determined) practical reason and appears in Immanuel Kant's Groundwork of the Metaphysics of Morals.
It is the reason that drives actions without any sensible incentives. Human reasoning chooses such actions simply because those actions are good in themselves; this is the nature of good will, which Kant argues is the only concept that is good without any justification, it is good in itself and is a derivative of a transcendental law which affects the way humans practically reason (see practical philosophy).
Famous quotes containing the words pure, practical and/or reason:
“Above all, however, the machine has no feelings, it feels no fear and no hope ... it operates according to the pure logic of probability. For this reason I assert that the robot perceives more accurately than man.”
—Max Frisch (1911–1991)
“No delusion is greater than the notion that method and industry can make up for lack of mother-wit, either in science or in practical life.”
—Thomas Henry Huxley (1825–95)
“And therefore, as when there is a controversy in an account, the parties must by their own accord, set up for right Reason, the Reason of some Arbitrator, or Judge, to whose sentence, they will both stand, or their controversy must either come to blows, or be undecided, for want of a right Reason constituted by Nature; so is it also in all debates of what kind soever.”
—Thomas Hobbes (1579–1688)